Ok guys , I hate to ask , but I just dont have the time to read through old threads .. I barely have time to work on the boat for that matter .....1992 prostar 205 , I am about to install all my stereo and second battery since spring is coming and I have a couple questions about the battery/stereo wiring ..

1. When installing the second battery , does it matter how long the cables are or do they need to be the same length as the first batterys cables ? I know they need to be the same guage wire , but what about the length ??

2. I plan on running the amplifiers on one battery and the boat off the other . Do I hook up the headunit power to the stereo battery or the boat battery ? Does it matter ?

3. When I install the perko switch , should I use an Isolator or just the perko switch by itself ?? In my old boat I just had the perko switch , it seemed to be fine and never had a problem , but I keep hearing the word ISOLATOR when I hear dual battery talk ..Does it help more than just the switch , or am I confused ?

4. When I install the perko switch , does it matter how close it is located to the battery ..?
When I say close I mean in "how many feet of wire" , not physically close ..

I have worked hard on the boat over the winter getting things in order , and this is my last PUSH b4 spring hits .. I am pretty good with wiring and stereo stuff , but these couple questions , even though fairly basic , have me stumped and are the only questions I have standing in my way of having this thing done for spring .. Any help is appreciated , and once again Im sorry for not spending hours on end searching for these answers b4 asking ...

1. What and where are the amps?
Where do you plan to install the 2nd battery?
Gauge depends on length and current draw / input, which depends on install and intended use.

2. My general guidelines are stereo dedicated batteries should AT LEAST equal number of amps. Might need to consider a 3rd battery. (especially if planning to cove much)
In general, I recomend using the same power source for all audio. There is a less chance of ground loop feedback issues. Also, playing the HU off stereo batteries you run less chance of running down the start battery by playing too long or leaving it on unintentionally. May need to go custom and run power direct to a pannel switch, isolating it from the rest of the pannel then connect to the HU if you want audio on a switch. Dont forget to properly fuse the switch, never know down the road what else gets attached to it.

3. An isolator is basically an electronic Perko that makes charging with the alternator less effort because it will automatically switch to charging the stereo bank. I had moderate luck with an isolator but as my power increased, I found it less useful.

4. Location - can be anywhere but shortest wire run is better from a cost and electrical resistance standpoint. Also, take ease of access with a crew in the boat into account if you will be switching it often, say from coved (1-isolate start battt) to board session (all-charge stereo bank) DONT FORGET TO SWITCH BACK WHEN DONE RUNNING.

**** Battery charger was not mentioned but a decent 10a+ charger should be installed to top off the stereo bank every night at a minimum.

1) No, cable length doesnt matter, but their gauge will be determined by length and intended loads.

2) Yes it matters. ALL audio gear needs to share the same battery source. If you are going to just run a traditional dual battery switch, then the amps and head-unit are best to be connected to the "C" post of the switch. All other boat electrical loads will do the same, except the auto bilge B+

3) A dual battery switch is an isolater/combiner, just a manual one. Adding in an isolater, whether its a diode type or relay type isolater/combiner will allow for both battery banks to be charged while engine is running and isolated from each other when engine is off. An ACR is great, but is not needed and not always best for every system.

4) The closer to the battery banks, the better, but it also needs to be somewhat convenient. As long as the gauge of any new cabling accounts for the distance and load, then cable length is only an additional cost.

thanks for the quick help guys , I pretty much knew some of this stuff , just trying to make sure before I go installing stuff .. I only want to do this ONCE ..We all know how tight it is working under the dash of an MC .. I appreciate the quick response .. Thanks again

Thanks for the input Lumberg , Im looking into the isolator and thinking about running one instead of the manual perko switch , I will be picking one up tommorrow at the boat place and getting started ..
I wish I had the space for the cooler in my 205 under the observer seat , I guess mastercraft didnt do that on my 1992 model ??.. I thought they all had that little spot there..??
It sure would help putting that 2nd battery in , I guess im stuck putting it in a battery box and just pushing it as far as I can get it up undernieth the passenger console .. I hate to do this , its gonna eat up the LITTLE BIT of space that mastercraft offered me ...My wife already hates not having a place to put stuff in this boat , there is just no storage , the storage under the bow seats holds NOTHING hardly , and if I put the battery under the console then Im really screwed for space ..
Has anyone gone crazy and mounted the battery in another spot other than under the console ??.. Like in the walkway under the bow filler cushion , or behind the driver seat undernieth the observer jumpseat that I have seen people make ?? There has got to be a place to hide a battery in this boat other than next to the gas tank and under the console ???

Passenger console is where most put an additional battery but you might consider under the front seats, there should be enough height there?

Thinking out of the box, consider a pair of 6v forklift batteries? These are usually taller and thinner, combined into a 36v bank. You might be able to mount one in each side compartment if you are a balance fanatic. We tend to put coolers, etc on the starboard side behind the drivers seat so mounting batteries on the port side balances the total load decent and has shorter total cable runs.
Check with a battery or industrial supply.